[Effect of clonidine on polyuria induced by alcohol, water or the lack of vasopressin in the rat].

1. The effects of two doses of clonidine (100 and 500 micrograms/kg sc) were compared on several types of experimentally induced diuresis (total value during 4 hours): alcohol or water loaded rats and Brattleboro rats (i.e. animals with congenital lack of vasopressin). 2. The two doses of clonidine alone increased the values of urine flow (fig. 1 and 3). 3. Clonidine, at a low dosage (100 micrograms/kg sc), potentiated the increase in urine flow induced by water overloading but remained ineffective in alcohol--loaded rats (fig. 1). 4. Clonidine, at a higher dosage (500 micrograms/kg sc) reduced alcohol--or water--induced diuresis (fig. 3). 5. In Brattleboro rats, clonidine decreased urine flow (100 micrograms/kg sc) or was without effect (500 micrograms/kg sc) (fig. 2). 6. These results suggest that relatively high doses of clonidine may be useful in treatment of alcohol with drawal in man: the drug could act as a sympatholytic and sedative central agent but could also decrease alcohol--induced diuresis by inhibition of vasopressin release.